The key is to find the small thing that easily lends itself to an upsell. For example, lots of people do a logo on places like fiverr for 5 bucks. But, if you want the .ai or .eps file, you have to pay the extra to get it, which is usually $20 extra. So, your $5 gig is now transformed to a $25 gig, and so on. So, it really does depend on the job you need done, and how you can structure a series of upgrades that make it worth your time.